
rerun assign on an empty testbed if the initial assign pass failed.
If assign failed on an empty testbed than It will fail with the error
message:
  Experiment can not be run on an empty testbed.  Please fix the experiment.

nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome